Soap bars can be prepared from a variety of long chain fatty acids derived from vegetable, animal and synthetic feedstocks. Examples of these feedstocks are tallow and coconut oil. It has been known for many years that the presence of a small proportion of free fatty acid in a soap bar can provide desirable consumer properties, for example creamy lather. The proportion of free acid will normally be in the range from 1% to 15% by weight of the bar and preferably in the 5% to 10% range. Usually, but not exclusively, the free acid will be derived from the shorter chain length feedstocks such as coconut oil.
A level of free fatty acid above 5% is usually required to obtain the benefit when the moisture level is about 8% to about 12%. With amounts of tallow above 70% in tallow/coconut charge the free fatty acid is preferably present at a level about 7.5%, more preferably above 10%.